A large supermarket may have as many as thirty five thousand (35,000) different items for sale. The items are generally disposed on shelves. Price tags are generally disposed below the items on the front of the shelves providing the support for the items. The tags are generally passive that is, they are prepared in advance and are affixed to the front of the shelves supporting the items. The tags may be made from a suitable material such as cardboard or a plastic and may be affixed to the shelves in a manner such that they can be easily removed from the shelves. The information on the tags may be typed or printed. This information may include the identity of the item, the supplier's or the stores trademark for the item, the price of the item, the price per unit (e.g. price per ounce or price per fluid unit) and any discount from a previously established price.
The prices of as many as ten percent (10%) of the items in a large supermarket are changed each week. This means that as many as thirty five hundred (3500) tags in a large supermarket may be changed manually each week. It is not uncommon to change the price of an item in the central processing unit in the market and to forget to change the price of the tag identifying the item. This creates confusion, particularly at the cashier's counter, in the operation of the supermarket and sometimes resentment in the minds of the customers. Often the supermarket may have to provide the customer with the price indicated on the tag even though the true price indicated in the supermarket's central processing unit is higher than such indicated price.
Passive tags on shelves as discussed above have vast acceptance because of apparent low cost and because of widespread use for a considerable number of years. The apparent low cost must be factored, however, with the large numbers of tags required to be changed weekly, the errors associated with the preparation of the new tags and the costs in preparing the new tags, in removing the outdated tags from the shelves and in affixing the updated tags to the shelves. For large supermarkets, the services of a clerk on a full time basis are often required to prepare the new tags, remove the outdated tags from the shelves and affix the updated tags to the shelves.
Various attempts have been made to replace the passive approach to updating tags as discussed above with an active approach to updating the tags. For example, active tags have been changed from a central station by radio frequency (RF) links. In these systems, the information for changing a tag is provided in the central processing unit and is transmitted by the central processing unit to the tag. The price presentation in the tag is then changed by circuitry in the tag in accordance with this transmitted information. A major problem with this system is that each tag has been powered by its own battery. As is well known, batteries have limited shelf lives. This has required considerable maintenance to replace defective or low powered batteries. Even with such considerable maintenance, the batteries are not replaced immediately after they fail. This has prevented price information from being presented on tags on shelves for items whose batteries have failed and have not been replaced.
Another active approach to updating tags in markets has been to use infra red energy. However, there have been problems of line of sight between the sources of the infra red energy and the tags energized by such sources. For example, the infra red sources have generally been overhead, usually at the ceilings in the supermarkets. As a result, there has often been a considerable distance between the infra red sources and the tags, particularly with respect to the tags on the lower shelves. Furthermore, there has been a problem with respect to the line of sight between the infra red sources and the tags on the shelves, particularly the tags on the lower shelves. These problems have required high powered infra red sources to be used and bright responses from the tags to be provided. When batteries have been used to power the tags in such systems employing infra red energy, the batteries have had short lives in view of the intensity of the infra red energy required.
Other systems have utilized coaxial lines, wires and/or fibers to transmit price information from a central processing unit to the different tags in a market. However, such systems have required extensive installations and have also required extensive maintenance after installation. Furthermore, such systems have also limited the positions where the tags can be located in the supermarket. For example, such systems do not allow simple, free-floating displays on store floors.
As will be seen, an active system has not been provided as yet which will meet all of the following criteria:
1. Low cost of installation; PA0 2. Low cost of maintenance; PA0 3. Low cost of operation; PA0 4. No batteries in the tags; PA0 5. Reliability of operation; PA0 6. Simplicity of operation; and PA0 7. A handheld unit including a memory for storing price information for the different items in a supermarket.